So it was understandable that near the end, the two were found together, overcome by smoke in a second-floor bedroom of their Crane Street home, which burned early Monday.

"It's a terrible tragedy for the whole neighborhood," said one neighbor, who didn't want his name used for fear of further shining a spotlight on a very private family. "This was a mother who really cared for her daughter, and I'd rather just leave it at that."

Gerrity, 47, and her 19-year-old daughter were found unconscious by firefighters and transported to Bridgeport Hospital, where they later died.

O'Neill attended special programs at Fairfield Warde High School. "Katie" was described as "severely handicapped" by one neighbor, and also by another as a smiling young woman with a sweet disposition.

"They were just lovely, lovely people," said another neighbor, her voice cracking with emotion. "Maureen was such a great mother."

Fire officials said they got a call just before 1 a.m. Monday from a neighbor who reported that flames were "pouring" out of Gerrity's house.

Assistant Fire Chief George Gomola was the first to arrive and reported that two people were trapped.

"We encountered extremely heavy fire condition on arrival," Gomola said later. "Through a coordinated team effort, we were able to knock down the bulk of the fire while initiating an aggressive interior search, with firefighters Jeff DeNitto, Will Malkin and John Calandriello pushing through extreme heat in the second-floor stairwell to gain access to the bedroom where the occupants were located."

The cause of the fire at the two-story Cape was accidental, according to preliminary indications from fire investigators Monday evening. Intense heat destroyed much of the potential evidence, said Assistant Fire Chief Christopher Tracy.

A neighbor who asked not to be identified said she was awake and watching television after 1 a.m. Monday when she heard a police car rush down Crane Street. When she looked outside, the woman said she saw five fire trucks, two rescue vehicles and two ambulances in front of the Gerrity house.

"The flames were so high and the smoke so thick," the woman said.

There were no working smoke detectors found in the house, officials said, but there were two carbon-monoxide detectors, which were activated by the fire.

Officials said the first two firefighters to enter the house thought they had been burned on the wrist and knee. Tracy said they were checked out and were not injured, but their suspicions underscored how intense the heat was inside the home.

"To blow out those windows, you have to figure the fire was pretty far along," Tracy said.

Westport firefighters also were dispatched to the scene to assist the emergency operations, while other fire crews from Westport and Bridgeport provided backup coverage for Fairfield.

Fire Marshal William Kessler and members of his staff, police detectives and representatives from the state Fire Marshal's Office stayed at the scene for several hours Monday, investigating the cause of the fire.

The last house fire death in Fairfield was in 2009, when a late-night blaze destroyed two second-story units at the Quincy Condominiums on Hulls Highway. Shirley Smith, 88, was discovered dead in a neighboring unit; it was later determined she died from smoke inhalation.